The present invention relates to a die for granulation presses, particularly for the manufacture of feed granulates, consisting of a cylindrical, cross-sectionally circular center element having a plurality of granulation bores and connecting flanges formed on the two ends of the center element.
The known granulation presses consist of a die like that described above, in which two compression rollers, so-called crushing rollers, are mounted in an eccentrically rotatable manner, whereby the die rotates about the compression rollers at a speed of approx. 200 to 300 rotations per minute. One side of the die is clamped to the drive element by means of the connecting flange and on the other side a cover is placed on the flange. The pressure arising from the compression of the products between the rollers and the center element, which may rise as high as 200 tons maximum, the die is subject to a high, constant load. In order to assure a high wear resistance of the center element of the die, the entire die is made of hardened chrome steel, whereby in the working area of the center element there may be as many as approx. 3000 to 18,000 granulating bores of a diameter of from 2 to 20 mm. Because of the continuous load, the known dies of hardened chrome steel experience fatigue breaks after anywhere from 200 to 600 hours of operation. Because of this large range for the appearance of the breaks, it is not possible to predict the useful life, so that a continuous danger of injury and destruction is present for the operating personnel and for the machinery due to the material sent flying by a break, often weighing as much as 100 kg.